first sorry if some phrases or words doesn't sound right, is difficult to explain technical things in english!
after a year working on it, finally complete my Electric Biab setup, 100liters pot for 14g/52liters of finished product, dual 2kw elements with auto/manual control panel, electric stirrer and hoist, all on a mobile rack.
A couple of years ago i made this biab setup with low costs elements with simple manual regulators, but it was a pain to work with, always manually stirring, difficult to hold steady temperature and also had problem with schorched wort (here the link http://www.biabrewer.info/viewtopic.php?f=24&t=2437 ).
I choose the automatic stirrer path because i want that every brew is repeatable, distribute the heat evenly, mix the wort and keep the wort/water around elements in movement.
Stirrer is based on automotive wiper motor, with a couple of blades attached. Bag is hold to walls of the pot with a selfmade cage, everything inside and outside the Pot is stainless steel (304 or 316) or food grade silicone.
In future i could add a pump or use it in parallel with the stirrer, right now after few tests everything is working right.
Also made a control panel to automate everything with a raspberry Pi, wireless controlled. The panel has dual mode
- automatic: everything controlled via StrangeBrew Elsinore software (pid with ssr, digital thermo probe,etc.)
- Manual: old fashion way, manual on/off switches for Elements/stirrer, and regulation via SCR circuits for the elements.
here the detailed Control Panel build http://www.biabrewer.info/viewtopic.php?f=154&t=3527
Starting from the bottom...mounted a kitchen hood to remove steam (found a nice offer online) in the garage/brewery corner.
modified the stand built in 2013, now it has 4 wheels (lockable), add some soldered plate to reinforce the structure, after that used a stainless steel sheet (bended on the corners) to cover the top part.
I Made a "separation layer" so the bag doesn't touch the elements, used a perforated stainless steel sheet (2mm thick), cutted and bended on the sides and supported by large bolts with smooth body, everything is 304 SS.
Bought a SS bar (15mm x 15mm), made the hole and threaded for the wiper motor, rounded the upper side with a flex.
Working on the lid, holes for the stirrer shaft and supporting plate, flex cut for the charging/inspection door, installing it.
Wiper support plate. Blades made with 3 or 5mm sheet (don't remember) flex cutted then bended with a long bar, to give a direction for mixing the grain bed, then sanded and smooothed